And that is the problem with these anecdotal accounts. They vary greatly, and often are from the like minded people we surround ourselves with.
My old childhood friends, back from the OT era, universally love this movie. All hardcore SW fans that were turned off by the prequels. Alot of them are now in the film industry or ex film students, so that may be why they align more with critics. Who knows. But even the ones who don't at least have a strong like for the movie.
So if I were going off that experience alone, i would think all gen-xers loved the movie.
But your experience differs. So maybe it isn't a generational divide at all. Its what people are looking for in a movie. TLJ delivers for me on all the most important aspects of a movie. The ones where I find faults are generally aspects of a movie I can overlook. For another person, those aspects may be most important.
I know one guy who won't take a movie seriously if there's a single bad CG scene in it. Doesn't care about acting, script, plot, character, just production value. Now I have very little respect for that guy's opinion, but his criteria is clear even if it doesn't agree with mine.
At less extremes, that is true for all of us. We all have a different hierarchy of value in a movie. not dependent on age or any objective truth about what a movie should be. But based on our subjective preferences. That is the divide here. Not people who read the Thrawn trilogy, or the 15 people in the world who think AotC is the best Star Wars movie. Trying to place absolute value by generational divide is really a vast oversimplification.
